Four Foot Contours

This layer contains the obscured contours for Campbell County, Virginia. Contours for the project meet accuracy specification for 2' contours and 4' contours based on the source 1"=600' and 1'=1,200' photography, respectively. In areas of dense vegetation or shadow, it may be impossible for the stereo compilation technician to accurately see the ground. The operator places masspoints as best as possible, extending breaklines through shadowed areas or placing points on the ground as is visible through the vegetation. Since the ground is obscured, the contours cannot be guaranteed to meet accuracy specifications for the specified contour interval.本图层包含美国弗吉尼亚州坎贝尔县的受遮挡等高线数据。本项目的等高线分别基于1英寸=600英尺、1英寸=1200英尺的航摄数据源，满足2英尺、4英尺等高距的精度要求。在植被茂密或存在阴影的区域，立体编绘技术员可能无法准确辨识地面实际状况。作业人员将尽可能布设测点：将地形断裂线延伸至阴影区域，或在植被间隙可见的地面位置布设测点。由于地面存在遮挡，无法保证该指定等高距下的等高线满足既定精度要求。